MSc

The present investigation on “Seed maturity and seed longevity studies in snake gourd (Trichosanthes anguina L.) varieties” was carried out in the Department of Olericulture, College of Horticulture, Vellanikkara during the year 2010-2012 with the objective of standardising the physiological maturity of snake gourd varieties for better seed quality, understanding the influence of fruit size and position of seeds within the fruit on seed quality and studying the effect of storage conditions on seed quality and longevity.

Investigation on physiological maturity indicated that fruits attained maximum weight and length when harvested at 36 days after anthesis in Baby and 39 days after anthesis in Kaumudi. Seed quality parameters viz., number of seeds per fruit, fresh and dry weight of seeds, 100 seed weight, germination percent, speed of germination, seedling length and vigour index were maximum in fruits harvested at 36 and 39 days after anthesis in Baby and Kaumudi respectively. Morphological characters of the fruit at this stage included change in fruit colour turning red at the tip portion and the placenta colour changing to red. Seeds got detached from the mucilaginous placenta and seed coat became hard with well developed ring on the seed surface.

Large sized fruits recorded maximum values for length and weight of fruits, and number and weight of seeds. Seed quality parameters viz., germination percent, seedling length and vigour index were found to be high in seeds obtained from medium sized fruits when compared to large and small sized fruits in both the varieties.

Among the different portions of the fruit (pedicel, middle and stylar regions), middle portion recorded higher fruit weight, number and weight of seeds, germination percent and vigour index in small, medium and large sized fruits compared to pedicel and stylar regions in both the varieties.

The effect of storage conditions influenced seed quality parameters in both varieties of snake gourd. Maximum germination, seedling length and vigour were obtained at 3rd month in ambient storage condition and 4th month in A/C storage condition and a decline in these parameters was observed in later months of storage. Lowest values for germination, seedling length and vigour were recorded at 12th month in both the conditions of storage (ambient and A/C) in both varieties. Seeds stored under A/C condition exhibited higher quality compared to those stored under ambient condition and Kaumudi recorded higher values for seed quality than Baby. Activity of the enzyme dehydrogenase was found to decrease over storage period in both the varieties studied. Generally values were higher under A/C storage condition than open condition and among varieties, values were slightly higher in Kaumudi than Baby. Electrical conductivity values of the seed leachate were found to increase with increase in storage period under ambient and A/C conditions of storage in both the varieties namely Baby and Kaumudi and the increase was more in seeds stored in open condition than A/C condition.